Safety is an important factor in elevator systems and escalator systems. These systems may comprise a number of safety devices providing signals for a controlling unit, for example, a safety circuit board. The controlling unit then determines whether operation of an elevator or an escalator is possible.
PESSRAL/PESSRAE (Programmable Electronic System in Safety Related Applications for Lifts/Programmable Electronic System in Safety Related Applications for Escalators) standards require that safety output relays are tested at least once a day. This means that an elevator or an escalator has to be stopped in order to perform the relay testing.
In certain locations where there is continuous heavy people traffic, escalator safety regulations may require that escalators run continuously through a service interval that can be several months long. However, in order to test a safety output relay of the escalator, the escalator must be stopped.
Thus, it would be beneficial to have a solution that would alleviate at least one of these drawbacks.